The present invention relates to a method for setting a safety belt in a vehicle as well as an adjusting apparatus for a safety belt in a vehicle.
For a function which is as optimal as possible of a safety belt as part of a restraint system in a vehicle, it is important amongst other things that the safety belt is correctly set and runs according to its intended use, for example with a three-point belt over the chest and pelvic region of a vehicle occupant. In this case, a preset position of a deflection point for the safety belt in the region of the shoulder of a vehicle occupant on the vehicle seat or a vehicle part fixed to the bodywork is frequently only a compromise solution for a vehicle occupant of average size and in an optimally adopted seating position. Therefore, for many years it has been known to design a deflection point to be manually adjustable and which, for example, is provided for a front vehicle seat on the B-pillar of the vehicle in order to deflect the safety belt in the direction of the shoulder of a vehicle occupant. A vehicle occupant is thus able to set the height of the deflection point in order to adapt the path of the safety belt to the size and/or the (current) seating position thereof. In this case, the safety belt at the deflection point is generally guided out of the cladding, for example for a front vehicle seat the cladding of the B-pillar or a backrest of a vehicle seat. A portion of the safety belt fastened on the bodywork side, therefore, is installed behind the cladding or inside the vehicle seat.
Whilst in the event of a crash the action of the safety belt is considerably improved if the deflection point thereof has been adapted in the shoulder region to the size of the vehicle occupant, it is frequently seen in practice that a vehicle occupant does not undertake an accurate setting of the deflection point and/or a belt guiding element defining the deflection point. Even if, as in high-quality vehicles, it is possible to set the deflection point of the safety belt in the shoulder region by an externally applied force, generally by an electromotive drive, such a setting is only undertaken relatively rarely before the start of the journey.
Therefore, a mechanism in an adjusting apparatus for a safety belt is already proposed in WO 97/33 777 A1, in which a belt guiding element, via which a safety belt on an upper face of a backrest is deflected and is guided in the direction of the shoulder of a vehicle occupant fastened in by the safety belt, is able to be adjusted such that the position of the belt guiding element is altered depending on the size of the vehicle occupant using the safety belt. The belt guiding element in this case is designed in the form of a guide pin which is provided on a disk which is rotatably mounted inside the backrest. The adjusting apparatus disclosed in WO 97/33 777 A1, however, is only able to be used for safety belts integrated directly in the backrests of a vehicle seat. Additionally, however, an optimized setting of the path of the safety belt in the event of a crash is possible to a limited extent, since the belt guiding element is only rotatably mounted about one axis and also no means are provided for monitoring the correct position of the belt guiding element.
In this connection WO 2005/090118 A1 proposes to set automatically the position of a deflection point for a safety belt in the region of a shoulder of a vehicle occupant by means of at least one sensor device. In this case, a video sensor unit is proposed in order to detect, for example, the size of the vehicle occupant and the current seating position thereof and, depending thereon, to set not only the safety belt but also the position of a headrest, the backrest and a longitudinal seating position. Such an adjusting apparatus, by means of which an automatic setting in particular of an upper deflection point of a safety belt takes place individually for a vehicle occupant, certainly represents a marked improvement relative to the adjusting apparatus of WO 97/33777 A1. Such an adjusting apparatus is, however, very costly. In particular, the processing and evaluation of the data detected via a video sensor unit is generally extremely complex and thus hitherto an appropriate sensor device has rarely been able to be used in practice.